Contents

Range and distribution

Pumpkinseed sunfish have been introduced throughout all of North America. They can now be found from Washington and Oregon on the Pacific Coast to Georgia on the Atlantic Coast and are primarily found in the north-eastern United States. The pumpkinseed’s natural range is from New Brunswick down the east coast to South Carolina. It then runs inland to the middle of North America, and extends through Iowa and back through Pennsylvania. The greatest populations of pumpkinseed sunfish are in the northeastern region of the United States as they are rarely found in the south-central or southwestern region of the continent.[1] In Europe, the pumpkinseed is considered an invasive species. They were introduced to European waters, and could outcompete existing fish, therefore making them invasive or alien species.[2]

Physical description

Pumpkinseeds typically are 6-8 inches in length, but can grow up to 10 inches. They typically weigh less than 1 pound, with the world record being 1 pound 6 ounces.[citation needed] They are orange, green, yellow or blue in color, with speckles over their sides and back and a yellow-orange breast and belly. The coloration of the ctenoid scales of the pumpkinseed is one of the most vibrant of any freshwater fish and can range from an olive-green or brown to bright orange and blue. The sides are covered with vertical bars that are a faint green or blue, which are typically more prevalent in female pumpkinseeds. Orange spots may cover the dorsal, anal, and caudal fins and the cheeks have blue lines across them. The pumpkinseed is noted for the orange-red spot on the margin of its black gill cover. The pectoral fins of a pumpkinseed can be amber or clear, while the dorsal spines are black. Pumpkinseeds have a small body that is shaped much like that of a pumpkinseed, giving them their common name. They have a small mouth with an upper jaw stopping right under the eye.[3]

Pumpkinseeds are very similar to that of a bluegill, and are often found in the same habitats. One difference between the two species is their opercular flap. The flap is black in both species, but the pumpkinseed has a crimson spot in the shape of a halfmoon on the back portion of its opercular flap. Pumpkinseeds have 7-8 vertical irregular bands on their sides that are duller in color compared to the bluegill.[4]

Habitat

Pumpkinseeds typically live in warm, calm lakes, ponds and pools of creeks and small rivers with plenty of vegetation. They prefer clear water where they can find shelter to hide. They tend to stay near the shore and can be found in numbers within shallow and protected areas. Pumpkinseeds are active during the day and rest near the bottom in protected or covered areas such as submerged logs during the night. They will feed at all water levels from the surface to the bottom in the daylight, and their heaviest feeding will be in the afternoon. Pumpkinseed sunfish usually travel together in schools that can also include bluegills and other sunfish.[5]

Pumpkinseeds are more tolerant of low oxygen levels than bluegills are, but less tolerant of warm water. Groups of young fish school close to shore, but adults tend to travel in groups of 2-4 in slightly deeper yet still covered waters. Pumpkinseeds are active throughout the day, but they rest at night near the bottom or in protected areas in rocks or near submerged logs.

Dietary habits

Pumpkinseeds feed on a variety of small food both at the surface of the water and at the bottom. Among their favorites are insects, mosquito larva, small mollusks and other crustaceans, worms, minnow fry and even other smaller pumpkinseeds. Occasionally they will feed on small pieces of vegetation as well. Pumpkinseed sunfish have a terminal mouth, allowing it to open at the anterior end of the snout.[1]

Pumpkinseed sunfish that live in waters with larger gastropods have larger mouths and associated muscles in order to crack the shells of the larger gastropods.[6]

Human importance

The pumpkinseed sunfish are typically very likely to bite on a worm, which makes them easy to catch while fishing. Many anglers consider the pumpkinseed to be a nuisance fish, as it bites so easily and frequently when the fisherman is attempting to catch something else. The pumpkinseeds are very popular with young fisherman, however, due to their willingness to bite on worms, their abundance, and their close locations to the shore. Although many people consider the meat of a pumpkinseed to be good tasting, it is typically not a popular sport fish due to its small size.[1]

Because they tend to remain in the shallows and feed all day, pumpkinseeds are relatively easy to catch from shore. They will bite at most bait—including garden worms, insects, leeches, or bits of fish. They will also take small artificial lures and can be fished for with a fly rod with wet flies or dry flies. They will also hit at grubs early in the winter but are less active from mid- to late winter. They may be easy to catch and popular with the youngest anglers, but pumpkinseeds are often sought by adults as well. The fish do put up an aggressive fight on line, and they have an excellent flavor and are low in fat and high in protein.[7]

Conservation status

The pumpkinseed sunfish is very common and is not listed in IUCN status or CITES Appendix. Spawning grounds of the pumpkinseeds can be disturbed by shoreline development and shoreline erosion from heavy lake use. Their susceptibility to silt and pollution makes the pumpkinseed a good indicator of the cleanliness and health of water.[5]

Reproduction and life cycle

Once water temperatures reach 55-63 degrees F in the late spring or early summer, the male pumpkinseeds will begin to build nests. Nesting sites are typically in shallow water on sand or gravel lake bottoms. The males will use their caudal fins to sweep out shallow, oval-shaped nesting holes that stretch about twice the length of the pumpkinseed itself. The fish will remove debris and large rocks from their nests with their mouths.

Nests are arranged in colonies consisting of about 3-15 nests each. Oftentimes, pumpkinseeds will build their nests near bluegill colonies, and the two species will interbreed. Male pumpkinseeds are vigorous and aggressive and will defend their nests by spreading their opercula. Because of this aggressive behavior, pumpkinseeds tend to maintain larger territories than bluegills.

Females arrive after the nests are completed, coming in from deeper waters. The male then releases milt and the female releases eggs. Females may spawn in more than one nest, and more than one female may use the same nest. Also, more than one female will spawn with a male in one nest simultaneously. Females are able produce 1,500 to 1,700 eggs, depending on their size and age.

Once released, the eggs stick to gravel, sand, or other debris in the nest, and they hatch in as little as three days. Females leave the nest immediately after spawning, but males remain and guard their offspring. The male guards them for about the first 11 days, returning them to the nest in his mouth if they stray from the nesting site.

The young fish stay on or near the shallow breeding area and grow to about 2 inches in their first year. Sexual maturity is usually achieved by age 2. Pumpkinseeds have lived to be 12 years old in captivity, but in nature most do not exceed 6–8 years old.[8]

Adaptations

A young pumpkinseed with visible spines and gill plates

The pumpkinseed sunfish has adapted in many ways to the surroundings that it lives in. Its skin reflects camouflage for its habitat. The pattern that appears on the pumpkinseed resembles that of the sunlight patterns that reflect on the shallow water of bays and river beds.

The pumpkinseed sunfish has developed a specific method of protection. Along the dorsal fin, there are ten to eleven spines, and three additional spines on the anal fin. These spines are very sharp which aid the fish in defense. The pumpkinseed has the ability to anticipate approaching predators (or prey) via a lateral line system allowing it to detect changes or movements in the water using different mechanical receptors.

The bright colored gill plates of the pumpkinseed sunfish also serve as a method of protection and dominance. Also known as an eye spot, the dark patch at the posterior of the gill plate provides the illusion that the eye of the fish is larger and positioned further back on the body, thusly making the fish itself seem up to four times larger than it actually is. When a pumpkinseed feels threatened by a predator, it will flare its gills to make it seem larger in size, and show off the flashy red coloration. Males of the species will also flare their gills in the spring spawning season in a show of dominance and territoriality.

In the southern most regions of its distribution, the Pumpkinseed Sunfish has developed a larger mouth opening and abnormally large jaw muscles to aid in feeding. In the southern region the Pumpkinseed Sunfish's primary forage is small crustaceans and mollusks. The larger bite radius and enhanced jaw muscles allow the Pumpkinseed Sunfish to crack the shells of their prey to attain the soft flesh within, thus providing one common name of 'Shellcracker'.[6]

Etymology

Lepomis, in Greek, means 'scaled gill cover' and gobbosus means 'wide margin'. The defining characteristic of a pumpkinseed sunfish is the bright orange spot at the tip of the ear flap. The pumpkinseed sunfish is widely recognized by its shape of a pumpkinseed, which is where its common name comes from.[9]